1. Field of the Invention
The present invention relates to an axle structure for a riding apparatus, such as a bicycle, and more particularly, an axle assembly adapted to be adjustable to offset the position of the axle from the geometric center of the wheel.
2. Discussion of the Related Art
Although the primary mode of ground transportation is the automobile, the bicycle continues to be a popular mode of transportation, particularly for recreational purposes. A typical bicycle enables a rider to obtain relatively high speeds, which is advantageous while traversing flat terrain or going downhill. With the advent of mountain bicycles, riders can enjoy such bicycles in a rugged mountain terrain with bumps and pot holes.
A bicycle axle is a major driving part to a bicycle since it transfers the force received from two cranks to a driving wheel which then drives the bicycle. A conventional bicycle has a concentric wheel with an axle in the center thereof to drive the bicycle. The position of the axle cannot be adjusted.
Known bicycle axle structure includes U.S. Pat. No. 5,553,878 to Davignon et al. The device disclosed in the Davignon patent is directed to an adjustable riding toy in both bicycle and tricycle forms. The bicycle is equipped with at least one wave ride wheel allowing a rider to change between a smooth ride and an up-and-down ride. This is accomplished by providing a wheel having a plurality of axle apertures therein. By placing the axle in one of the axle apertures, the wheel of the bicycle can be of a concentric shape or an eccentric shape.
While the above device fulfills its particular objectives and requirements, one disadvantage is that the axle and wheel assembly has to be physically disassembled from the bicycle frame. In particular, the axle has to be removed from one axle aperture of the wheel and then replaced into another axle aperture prior to re-fitting with the bicycle frame. This disassembling and re-assembling requires mechanical tools and effort and is therefore very cumbersome and discouraging.